Largest Batch of Earth-size Habitable Zone Planets Found Orbiting TRAPPIST-1

An image showing the exoplanets of the TRAPPIST-1 planetary system based on NASA Spitzer data.

This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets' diameters, masses and distances from the host star, as of February 2018.

NASA/JPL-Caltech

The most studied planetary system, aside from our own solar system, lies about 40 light-years away. We've looked at the seven rocky exoplanets orbiting the TRAPPIST-1 star with ground and space telescopes like Spitzer, Kepler, Hubble, and, now, the James Webb Space Telescope.

In March 2023, the first science from the Webb telescope was released. An analysis of TRAPPIST-1b, the innermost planet, revealed its dayside temperature and found little evidence of an atmosphere.

In a press release on February 22, 2017, NASA announced the discovery of the most Earth-sized planets found in the habitable zone of a single star, called TRAPPIST-1. This system of seven rocky worlds–all of them with the potential for water on their surface – is an exciting discovery in the search for life on other worlds. There is the possibility that future study of this unique planetary system could reveal conditions suitable for life.

In February 2018, closer study of the seven planets suggested that some could harbor far more water than the oceans of Earth, in the form of atmospheric water vapor for the planets closest to their star, liquid water for others, and ice for those farthest away. The study pinned down the density of each planet more precisely, making TRAPPIST-1 the most thoroughly known planetary system apart from our own.

A 2021 study revealed more about TRAPPIST-1 planets. They are likely made of similar stuff, but they are different from Earth. That could mean they all contain about the same ratio of materials thought to compose most rocky planets, like iron, oxygen, magnesium, and silicon. But if this is the case, that ratio must be notably different than Earth's: The TRAPPIST-1 planets are about 8% less dense than they would be if they had the same makeup as our home planet.

Use your mouse or fingertip to experience a 360 view. On mobile, move your phone to see sky, ground and horizon. This is an artist's interpretation.

An artist's illustration of TRAPPIST-1d takes you to the surface of the third planet from the red TRAPPIST-1 star. From here, the star looms larger than our Sun and its light casts a red glow across the sky. Look up, and you may catch a glimpse of its six sister planets, as visible as our Moon is from Earth. View on YouTube

Multimedia

Planet hop from TRAPPIST-1 e

Take a trip with the Exoplanet Travel Bureau to the fourth planet in the TRAPPIST-1 system, TRAPPIST-1 e, a world swimming in water in perpetual twilight. Its sister planets gracefully light up the sky, promising another adventure just a hop away.

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An artist's fantasy of the surface of TRAPPIST-1e, a stop on a tour of this seven-world system.

NASA/JPL-Caltech

Interact with the TRAPPIST-1 system in 3D
You can fly through the TRAPPIST-1 planets and see an artist's concept of the surfaces on your phone or with a desktop app. Compare each planet to Earth or Jupiter, compare the TRAPPIST-1 system to our solar system, and see how far the habitable zone extends.

With the touch of a screen or the click of a mouse, you can visit the newly discovered TRAPPIST-1 system in the our Exoplanet Catalog. It contains every exoplanet discovery, powered by NASA's Exoplanet Archive, the official database used by professional astronomers engaged in exploring new worlds.
TRAPPIST-1 System in 3D

Exoplanet lineup — This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets' diameters, masses and distances from the host star, as of February 2018. Credit: NASA/JPL-Caltech. Full resolution

Trappist-1 Planets Infographic — This chart shows, on the top row, artist concepts of the seven planets of TRAPPIST-1 with their orbital periods, distances from their star, radii, masses, densities and surface gravity as compared to those of Earth. Credit: NASA/JPL-Caltech. Full resolution

Comparison w solar system — All seven planets discovered in orbit around the red dwarf star TRAPPIST-1 could easily fit inside the orbit of Mercury, the innermost planet of our solar system. In fact, the proportions of the TRAPPIST-1 system look more like Jupiter and its moons. Credit: NASA/JPL-Caltech. Full resolution

TRAPPIST-1 beauty shot — This illustration shows the seven Earth-size planets of TRAPPIST-1. The image does not show the planets' orbits to scale, but highlights possibilities for how the surfaces of these intriguing worlds might look. NASA/JPL-Caltech. Full resolution

Comparing TRAPPIST-1 to the Solar System — This graph presents known properties of the seven TRAPPIST-1 exoplanets (labeled b through h), showing how they stack up to the inner rocky worlds in our own solar system. Credit: NASA/JPL-Caltech. Full resolution
NASA/JPL-Caltech

TRAPPIST-1 planet lineup — This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets’ diameters, masses and distances from the host star, as of Feb 2017. Full resolution

System Transit — The TRAPPIST-1 system consists of seven Earth-sized planets orbiting a red dwarf star. Full resolution

TRAPPIST-1 surface artist's concept — This artist's concept allows us to imagine what it would be like to stand on the surface of the exoplanet TRAPPIST-1f, located in the TRAPPIST-1 system in the constellation Aquarius, as of Feb 2017. Full resolution

Spitzer Data Plot — This data plot shows infrared observations by NASAs Spitzer Space Telescope of a system of seven planets orbiting TRAPPIST-1, an ultracool dwarf star, as of Feb 2017. Full resolution

Planets laid over habitable zones — Three of the TRAPPIST-1 planets – TRAPPIST-1e, f and g – dwell in their star’s so-called “habitable zone,” as of Feb 2017. Full resolution

Jupiter and Major Moons — A comparison of the TRAPPIST-1 system to our solar system. The close orbits of the TRAPPIST-1 planets are reminiscent of Jupiter and its system of orbiting moons, as of Feb 2017. Full resolution
NASA/JPL-Caltech/R. Hurt, T. Pyl

before

after

Before and After

Trappist-1 system Spitzer findings

Before and after the discovery of four new planets

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